A vehicle comprises a motor (4) and a wet clutch (12) for transmission of torque output of the motor to road wheels of the vehicle and transmission of road load from the road wheels to the motor (4). The wet clutch is disengaged in response to a clutch disengagement control signal. Accounting for clutch drag state of the wet clutch, a controller (8) selects one out of various values as threshold (Voff). The controller (8) determines that the wet clutch be disengaged when a parameter indicative of the actual vehicle speed has a predetermined relationship with the threshold. The controller (20) generates the clutch disengagement control signal upon determining that the wet clutch be disengaged.